The present invention relates to spinal surgery, namely, implants utilized in fusing adjacent intervertebral bodies or the replacement of a vertebral body.
Back pain can be caused by many different maladies, not the least of which are problems that directly impact the intervertebral discs of the spine. Typical disc issues include, inter alia, degeneration, bulging, herniation, thinning and abnormal movement. One method of treatment of such disc problems that has been widely utilized in the field of spinal surgery is a spinal fusion procedure, whereby an affected disc is removed, and the adjacent vertebral bodies are fused together through the use of interbody spacers, implants or the like. In some instances, it may also be necessary to remove and replace an entire vertebral body. This is often accomplished through the use of a larger implant that acts to fuse together the vertebral bodies adjacent the removed vertebral body.
The aforementioned implants often rely upon mechanical features to ensure engagement between the devices and the bone of the existing vertebral bodies. This coupled with the normal compressive load of the spine acts to keep the implant in place until bone can grow from the existing vertebral bodies into and through the implant. To encourage the bone growth, the implants are often pre-loaded with bone growth promoting material and thereafter placed into the spine. Bone growth promoting material may include naturally occurring bone, artificial materials or the like.
To further ensure a strong implant-bone connection, some existing implants include an area formed of porous material that allows bone to grow into it. Although there is little doubt that the bone growth into the implant is beneficial in maintaining an implant in place, these implants are often very difficult (and thusly, expensive) to manufacture. Additionally, existing implants that implement porous material do so in a limited manner. Often times, because of manufacturing or strength concerns or the like, the porous material is limited to a thin layer covering the upper and lower surfaces of the implant, which only allows for a small amount of bone to grow into the implant.
Therefore, there exists a need for an improved spinal implant that employs a significant amount of porous material, yet remains cost efficient and maintains the necessary strength required of a spinal implant.